At about 10 p.m. on April 20, 2010, the first of three explosions erupted on the Deepwater Horizon, a BP-leased rig drilling an exploratory oil well about 50 miles off the coast of Louisiana. The platform was soon engulfed in fire, killing 11 men and injuring 17. The rig sank two days later as the first reports of an oil leak began circulating.

The well would not be declared dead until September 19. In the five months between April and September, 206 million gallons of oil spewed into the Gulf, wrecking the coast's fishing and tourism industries; fouling beaches from Texas to Florida and leading to what Ret. Adm. Thad Allen, the national incident commander, called the 'largest peacetime mobilization' in American history.

The oil has been removed from the beaches, but the economic, ecological and psychological effects of the spill are likely to linger for years. The interactive timeline below traces the disaster from the explosion to the final sealing of the well.